X4317 Case Hardening Steel |
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| X4317 is a 1.8% chromium - nickel - molybdenum high hardenability, case hardening (carburizing) steel, generally supplied in the annealed condition with a maximum brinell hardness of 229 (Rc22).
Characterised by high core strength and toughness in medium to large sections with case hardness up to Rc62 when carburized, hardened and tempered.
X4317 can also be used (uncarburised) as a high tensile steel, which when suitably hardened and tempered can be utilized for various applications requiring good tensile strength and toughness.
Pre hardened and tempered (uncarburized) X4317 can be further surface hardened by nitriding but will not respond satisfactorily to flame or induction hardening due to its low carbon content.
X4317 (carburized) is used extensively by all industry sectors for components and shafts requiring high surface wear resistance, high core strength and impact properties.
Typical uses are: Heavy Duty Bushings and Bearings, Cam Followers, Clutch Dogs, Compressor Bolts, Extractors, Fan Shafts, Heavy Duty Gears, Pump Shafts, Sprockets, Tappets, Wear Pins, Wire Guides etc..
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| Colour Code | Stocked Sizes | ||
Red and White (Bar End) |
Rounds | 24 mm to 660 mm Diameter |
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| Bar Finish | |||
| Peeled, Turned or Hot Rolled | |||
| Related Specifications | |
| Australia | AS1444 - 1996 X4317/X4317H |
| Germany | W.Nr 1.6587 DIN 17210 17CrNiMo6 |
| Great Britain | BS970: PART 3: 1991 820M17/822M17 BS970: 1955 - EN354/EN355 |
| USA | SAE 4317 AISI 4317 |
| Chemical Composition | ||
| Min. % | Max. % | |
| Carbon | 0.15 | 0.20 |
| Silicon | 0 | 0.40 |
| Manganese | 0.40 | 0.60 |
| Nickel | 1.40 | 1.70 |
| Chromium | 1.50 | 1.80 |
| Molybdenum | 0.25 | 0.35 |
| Phosphorous | 0 | 0.04 |
| Sulphur | 0 | 0.04 |
| Mechanical Property Requirements - As Supplied to AS1444 - 1996 X4317 | ||||||||||||||||||
| Annealed Condition - Brinell Hardness 229 Maximum |
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| Typical Mechanical Properties - Annealed | ||||||||||||||||||
| Tensile Strength Mpa | 700 | |||||||||||||||||
| Yield Strength Mpa | 520 | |||||||||||||||||
Elongation on 5.65 % |
23 | |||||||||||||||||
| Hardness | HB | 200 | ||||||||||||||||
| Rc | 15 | |||||||||||||||||
| Typical Mechanical Properties - Water Quenched at 830 oC and Tempered as Indicated * | ||||||||||||||||||
| Section Size mm | 11 | 30 | 63 | |||||||||||||||
| Tensile Strength Mpa | Min | 1180 | 1080 | 980 | ||||||||||||||
| Max | 1420 | 1320 | 1270 | |||||||||||||||
| Yield Strength Mpa | Min | 835 | 785 | 685 | ||||||||||||||
| Elongation on 5.65 % |
Min | 7 | 8 | 8 | ||||||||||||||
| Impact Charpy J | Min | 41 | 41 | |||||||||||||||
| Hardness | HB | 350 - 415 | 320 - 385 | 290 - 375 | ||||||||||||||
| Rc | 39 - 44 | 35 - 42 | 31 - 41 | |||||||||||||||
| Forging | |||||
| Heat to 1150 oC and hold until temperature is uniform throughout the section. Soaking time at forging temperature should be as short as possible to avoid heavy scaling and excessive grain growth. This will vary depending on furnace conditions but 15 minutes per 25 mm of section may be used as a guide.
Do not forge below 850 oC.
Following completion of forging operation, work piece should be cooled as slowly as possible in sand or dry lime etc.
Note: Case hardening steels due to their low carbon content are less susceptable to cracking than medium or high carbon steels, and may therefore be heated and cooled more rapidly.
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| Heat Treatment | |||||
| Annealing | |||||
| Heat to 830 oC - 850 oC, hold until temperature is uniform throughout the section and cool in furnace. | |||||
| Caburizing |
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| Pack, salt or gas carburize at 900 oC - 930 oC, holding for sufficient time to develop the required case depth and carbon content, followed by a suitable hardening and tempering cycle to optimise case and core properties. | |||||
| Hardening |
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| Refer Refining & Hardening. | |||||
| Nitriding | |||||
| Not suitable for nitriding. | |||||
| Normalizing | |||||
| Heat to 860 oC - 900 oC, hold until temperature is uniform throughout the section. Soak for 10 - 15 minutes and cool in still air. | |||||
| Refining & Hardening | |||||
| Core Refine | |||||
| Slow cool from carburizing temperature and re-heat to 840 oC - 870 oC, hold until temperature is uniform throughout the section, quench as required in warm water, oil or air cool. Alternatively quench in salt bath held at 150 oC - 250 oC, followed by air cool. | |||||
| Case Refining |
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| Following core refining, re-heat to 780 oC - 820 oC, hold until temperature is uniform throughout the section, and quench in oil.
Temper immediately while still hand warm.
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| Single Refine* | |||||
| Direct Quench: Cool from carburizing temperature to 820 oC - 840 oC, hold until temperature is uniform throughout the section. Quench in oil.Temper immediately while still hand warm.
Or: Cool from carburizing temperature to room temperature, re-heat to 820 oC - 840 oC and hold until temperature is uniform throughout the section and quench in oil.
Temper immediately. *Suitable for fine grained steels only.
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| Stress Relieving | |||||
| Heat to 630 oC - 650 oC, hold until temperature is uniform throughout the section, soak for 1 hour per 25 mm section, and cool in still air. |
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| Tempering | |||||
| Heat to 150 oC - 200 oC as required, hold until temperature is uniform throughout the section, soak for 1 - 2 hours per 25 mm of section, and cool in still air. N.B. Tempering will improve the toughness of both case and core, with only a slight reduction in core strength and case hardness. It will also reduce the susceptibility of the case to grinding cracks. | |||||
| Notes on Heat Treatment | |||||
| Heating temperatures, rate of heating, cooling and soaking times will vary due to factors such as work piece size/shape also furnace type employed, quenching medium and work piece transfer facilities etc..
Please consult your heat treater for best results. |
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| Machining | |||||
| X4317 in the annealed as supplied condition has very good machinability and all operations such as turning, drilling,milling and tapping etc. can be carried out satisfactorily as per machine manufacturers recommendations for suitable tool type - feeds and speeds. | |||||
| Welding | |||||
| X4317 is readily weldable in the annealed as supplied condition. Following welding, the work piece immediately upon cooling to hand warm should be stress relieved at 630 oC - 650 oC if possible.
N.B. Welding in the carburized and heat treated condition is not recommended. |
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| Welding Procedure | |||||
| Welding of X4317 should always be carried out using low hydrogen electrodes - please consult your welding consumables supplier. | |||||
| Suggested Pre-heat Temperature | |||||
| Section | 25mm | 40mm | 50mm | 75mm | 150mm |
| oC | 250 | 275 | 300 | 350 | 400 |
| Post Welding | |||||
| Maximum cooling rate 100 oC per hour down to 100 oC, followed by cooling in still air. It is recommended that the work piece if possible is buried in sand or dry lime etc.. |
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Melbourne • Sydney
Albury • Adelaide • Brisbane
Mackay • Perth
